The present invention relates to a composition containing at least two kinds of hydrolyzed ethylene-vinyl acetate copolymers, and more particularly to a melt-blended resin composition having an improved melt-molding property.
A hydrolyzed ethylene-vinyl acetate copolymer having an ethylene content of 20 to 55% by mole and a degree of hydrolysis in vinyl acetate component of not less than 80% by mole has good properties such as oxygen impermeability, oil resistance, solvent resistance, antistatic property, perfume retaining property and mechanical characteristics. Therefore, the melt-molded articles of the hydrolyzed copolymer are used for various uses, including films, sheets and vessels for wrapping or packaging foods, electric and electronic device parts and machine parts.
However, the hydrolyzed ethylene-vinyl acetate copolymer has a defect of being hard to melt-mold due to its molecular structure as compared with common thermoplastic resins such as polyolefins and polystyrene. Therefore, in case of extrusion molding of the copolymer into a film, sheet or vessel, the uniformity in thickness is not always sufficient and also it tends to produce many fish eyes. Also, in case of injection molding of the copolymer, the injection pressure is not stabilized, whereby the mold shrinkage varies and no molded articles having a constant size are obtained.
It is an object of the present invention to provide a composition of hydrolyzed ethylene-vinyl acetate copolymers having an improved melt-moldability.
A further object of the invention is to provide a composition capable of being molded into articles having remarkably reduced fish eyes, a uniform thickness or an excellent dimensional stability.
These and other objects of the present invention will become apparent from the description hereinafter.